Biopsy samples have been obtained in a variety of ways in various medical procedures using a variety of devices. An exemplary biopsy device is the MAMMOTOME device from Ethicon Endo-Surgery, Inc. of Cincinnati, Ohio. Biopsy devices may be used under stereotactic guidance, ultrasound guidance, MRI guidance, or otherwise. Further exemplary biopsy devices are disclosed in U.S. Pat. No. 5,526,822, entitled “Method and Apparatus for Automated Biopsy and Collection of Soft Tissue,” issued Jun. 18, 1996; U.S. Pat. No. 6,086,544, entitled “Control Apparatus for an Automated Surgical Biopsy Device,” issued Jul. 11, 2000; U.S. Pub. No. 2003/0109803, entitled “MRI Compatible Surgical Biopsy Device,” published Jun. 12, 2003; U.S. Pub. No. 2007/0118048, entitled “Remote Thumbwheel for a Surgical Biopsy Device,” published May 24, 2007; U.S. Provisional Patent Application Ser. No. 60/869,736, entitled “Biopsy System,” filed Dec. 13, 2006; U.S. Provisional Patent Application Ser. No. 60/874,792, entitled “Biopsy Sample Storage,” filed Dec. 13, 2006; and U.S. Non-Provisional patent application Ser. No. 11/942,785, entitled “Revolving Tissue Sample Holder for Biopsy Device,” filed Nov. 21, 2007. The disclosure of each of the above-cited U.S. patents, U.S. patent application Publications, U.S. Provisional Patent Applications, and U.S. Non-Provisional patent application is incorporated by reference herein.
In some settings, it may be desirable to mark the location of a biopsy site for future reference. For instance, one or more markers may be deposited at a biopsy site before, during, or after a tissue sample is taken from the biopsy site. Exemplary marker deployment tools include the MAMMOMARK, MICROMARK, and CORMARK devices from Ethicon Endo-Surgery, Inc. of Cincinnati, Ohio. Further exemplary devices and methods for marking a biopsy site are disclosed in U.S. Pub. No. 2005/0228311, entitled “Marker Device and Method of Deploying a Cavity Marker Using a Surgical Biopsy Device,” published Oct. 13, 2005; U.S. Pat. No. 6,996,433, entitled “Imageable Biopsy Site Marker,” issued Feb. 7, 2006; U.S. Pat. No. 6,993,375, entitled “Tissue Site Markers for In Vivo Imaging,” issued Jan. 31, 2006; U.S. Pat. No. 7,047,063, entitled “Tissue Site Markers for In Vivo Imaging,” issued May 16, 2006; U.S. Pat. No. 7,229,417, entitled “Methods for Marking a Biopsy Site,” issued Jun. 12, 2007; U.S. Pat. No. 7,044,957, entitled “Devices for Defining and Marking Tissue,” issued May 16, 2006; U.S. Pat. No. 6,228,055, entitled “Devices for Marking and Defining Particular Locations in Body Tissue,” issued May 8, 2001; and U.S. Pat. No. 6,371,904, entitled “Subcutaneous Cavity Marking Device and Method,” issued Apr. 16, 2002. The disclosure of each of the above-cited U.S. patents and U.S. patent application Publications is incorporated by reference herein.
U.S. Pat. No. 7,329,414 issued Feb. 12, 2008 to Fisher et al., incorporated by reference herein, discloses examples of polymers that swell in the presence of fluids, including polymers that are hydrogels.
It may be desirable to deploy markers from a cannula type deployer into the biopsy site. The force to deploy the marker should be predictable so that deployment of the marker is reliable. The marker should not unintentionally fall out of the deployer, and the force to deploy the marker should not be excessive. It is desirable to control the fit of the marker in the cannula to ensure the marker is deployed only when intended, and that the deployment force is not excessive. For instance, if the marker is too loose in the cannula, it may fall out before it is intended to be deployed. On the other hand, if the marker fits too tightly in the cannula, it may be difficult to deploy the marker from the exit of the cannula.